Casting mold for hollow articles and core therefor



May 27, 1941. G. A. AGNEW 2,243,407

CASTING MOLD FOR HOLLOW ARTICLES AND CORE THEREFOR Filed Feb. 20, 1939 2 Sheets-Sheet l M y 27, 1941- e. A. AGNEW CASTING MOLD FOR HOLLOW ARTICLES AND CORE THEREFOR Filed Feb. 20, 1939 2 Sheets-Sheet 2 Patented May 27, 1941 UNE'EE SETTES CASTING MOLD FOR HOLLOW ARTICLES AND CORE THEREFOR George A. Agnew, East Haven, 001111., assignor to Malleable Iron Fittings Company, Branford, Conn, a corporation of Connecticut Application February 20, 1939, Serial No. 257,289

2 Claims.

This invention relates to the casting of hollow articles such, for example, as pipe fittings, but the invention is not to be considered as limited in this respect. It is particularly adapted for casting such hollow articles as are adapted to be interiorly threaded or otherwise treated interiorly in some manner by which the interior surface is removed, resulting in the removal of any casting scars upon this surface.

In the casting of hollow articles it is usual to provide a suitable mold having a mold cavity or cavities giving the cast articles the desired exterior shape, and arranging within the mold a core designed to give the article the desired internal shape. The gate through which the metal is poured has been in the past usually so disposed that it is in communication with the mold cavity either at the external surface of thefinished casting, or in some cases upon the end face thereof. In either case, the article cast by this method is left with a sprue scar after the sprue has been broken off. Such sprue scars must be removed by grinding or shearing, operations which are relatively expensive and add considerably to the cost of the finished article, particularly when such articles are made in large quantities and are relatively inexpensive per unit, such as pipe fittings for example.

The present invention relates to a mold and/r core of a particular formation whereby the mold gate will communicate with the mold cavity at the interior surface of the casting or at least at the inner corner of a face edge thereof, so that when the casting is removed from the mold the sprue will be joined to the casting principally at the interior surface thereof whereby any scar left by the removal of the sprue, even though a slight portion of such scar might be on the end face of the casting, will be removed by interior finishing operations, such, for example, as threading, chamfering or reaming, in the case of a pipe fitting.

One object of the present invention is the provision of a mold and core for casting hollow articles such that any sprue scar left from the casting operation may be removed by the normal finishing operations on the article, without the necessity of employing a special operation to remove such scar.

A further object of the invention is the provision of a mold and core for casting hollow articles whereby the molten metal may be introduced into the mold cavity through an opening at the inner surface of the finished casting.

A still further object of the invention is the provision of a novel mold and core for use in making hollow castings, the core being of such formation that it will permit the introduction of metal into the mold cavity adjacent the inner edge of the exterior face of the finished casting.

To these and other ends the invention consists in the novel features and combinations of parts to be hereinafter described and claimed.

In the accompanying drawings:

Fig. 1 is a top plan view of the lower half of a mold with the core arranged therein, which may be used in the employment of the present process;

Fig. 2 is a sectional view through the core and mold on line 2-2 of Fig. 1, both portions of the mold being shown in section;

Fig. 3 is a top plan view of a completed casting as removed from the mold with the sprue attached thereto; 1

Fig. 4 is a sectional view of one of the cast articles, showing the location of the connection between the sprue and'casting;

Fig. 5 is a view similar to Fig. 4 showing a single cast article after the sprue has been removed therefrom;

Fig. 6 is a top plan view of the casting shown in Fig. 5, and

Fig. '7 is a sectional view of the completed article after the internal threading operations have been completed.

To illustrate a preferred embodiment of my invention, I have shown and will describe my improved process as related to the casting of pipe fittings. It will be understood, however, that the novel principles involved are not limited in this respect but may be employed in the casting of other hollow articles and that the illustrated embodiment of the invention is given by way of explaining a preferred method of putting it into practice. v

In Figs. 1 and 2 of the drawings I have shown a mold comprising a lower portion l0 and an upper portion I I. The mold shown in the drawings is particularly adapted for the casting of internally threaded pipe elbows, and as it is expedient to cast a number of these articles at one operation I have shown a mold provided with four cavities l2, one at each corner thereof, each of such cavities being designed to cast a complete elbow. Between these cavities core seats are provided, the seats being of reduced diameter as compared to that of the cavities. Within this mold is placed a core designated generally by the numeral l3. This core preferably may be of rectangular form, as shown, having enlarged core members 84 at each corner designed to lie within the mold cavities, these core members being connected by portions l5 and I6 so that the entire core for making the four castings maybe formed in one integral piece and may be the usual sand core used in this kind of work. The mold may also be and preferably is a sand mold.

It will be noted that the connecting members l5 and I6 extend without the mold cavities and fill the space within the core seat whereby they cooperate with the contiguous portions of the mold to close these cavities at the ends and also support the core in proper position. It may also be noted that the connecting members l6 are slightly longer than the connecting members l5, resulting in a slightly greater spacing of the castings at the ends of these members.

The members l6 are provided with surface recesses ll formed therein, and as clearly shown in Figs, 1 and 2, formed below the normal surface outline of this part of the core. These recesses are slightly longer than the core seats whereby they extend across the respective core parts IE to points disposed within the adjacent mold cavities l2. That is to say, the end portions l8 of the recesses I! will lie slightly within the mold cavities so that the recesses are in communication with these cavities and permit the entrance of the molten metal to the mold cavities from the recesses.

The recesses I! are likewise in communication with the pouring gate I9 of the upper part of the mold, this gate being shown in dotted lines in Fig. 1. It will be noted from this figure that the gate is so shaped that while it communicates with the cavity i! it is in contact with only a very minute portion of the end face of the mold cavity or end face of the finished casting, thus providing a small opening as at 20, for the metal to pass into the mold cavity from the gate l9 and recess H. The slight portion of the end face of the mold cavity-Which is open to the gate I9 will lie at the inner edge or inner corner of the bore of the finishing casting so that it will be within the sphere of any internal finishing operations such as threading or reaming.

In Fig. 3 of the drawings I have shown a complete casting as it is removed from the mold, this casting consisting of four of the cast articles, in this case elbows 2!, the four elbows being connected by the sprue 22. The connection of the sprue with each of the castings is shown in this figure and in the sectional view of Fig. 4, wherein it will be observed that the sprue is connected to the castings at the inner corner of the end face thereof and projects over said end face to only a very small extent. Also, the connection between the sprue and each casting is over an area of very small width radially of the fitting while over a greater area or length circumferentially of the fitting.

The cast article as removed from the mold and shown in-Fig. 3 may then have the sprue removed or broken therefrom by any desired method, such for example, as being operated in a tumbling barrel. When the sprue has been broken from the castings the latter are in the form shown in Figs. and 6, wherein a slight sprue scar 23 remains at the inner corner of the end face of the casting, this sprue scar being disposed to a slight extent both on the end face and on the inside diameter of the casting.

As the illustrated device is a pipe elbow it is designed to receive internal threads 24, and the finished article after the threading operations is shown in Fig. 7. It will be noted that any sprue scar left upon the casting as shown in Figs. 5 and 6, is within the inside diameter of the threaded surface of the pipe, so that the scars are removed by the normal threading operations and a separate grinding or other scar removing operation is eliminated.

In making the casting, the core l3 isformed as shown in Fig. 1, having the surface recesses l1 formed therein. It will be found convenient to have a single recess IT in each portion l6 of the core, this recess extending to be in communication at both ends with the adjacent mold cavities. If desired, of course, two separate recesses I! may be formed upon each of the core portions l6, these separate recesses being in communication with the gate [9, and each being in communication with the adjacent cavity of the mold. After this core has been disposed between the halves of the mold in its proper position the metal may be poured through the gate [9. The metal thus poured will pass through the gate to the recesses l1 and thence into the mold cavities to form the molded articles as described, with the sprue being connected thereto only at the inner corners of the end faces thereof.

If desired, and as may be the case in the making of large castings, recesses similar to those shown at I! may be formed in both of the core parts l5 and I6, and said recesses connected to the mold gates so that the metal will enter each of the mold cavities at both ends thereof. It will, of course, also be apparent that the present method may be employed in casting articles where a single article only is cast in each mold instead of a plurality thereof, as shown in the present drawings. In the casting of a single article it is only necessary to have the core sections l5 and I6 extend from the single mold cavity, as shown, and the recesses formed in one or both of these extensions, as desired, and arranged to communicate with the pouring gate.

While I have shown and described a preferred embodiment of my invention, it will be understood that it is not to be limited to all of the details shown, but is capable of modification and variation within the spirit of the invention and the scope of the appended claims.

What I claim is:

1. A mold, a core therefor, said mold comprising a plurality of mold cavities connected by a horizontally disposed core seat, a core comprising a pair of core members adapted to be disposed within the cavities, and a part connecting said core members, said connecting part being seated on the core seat and having a surface recess therein extending longitudinally thereof to communicate at its ends with the mold cavities at the inner edge portion of said cavities, and said mold being provided with a pouring gate communicating with an intermediate part of said recess.

2. A mold for a multiple casting, said mold comprising a'plurality of mold cavities connected by a core seat, a core comprising core members each adapted to be disposed within one of the cavities, and a core-supporting portion connected to said core members and seated on the core seat, said portion having a surface recess therein extending from one cavity to the other at each end of the core seat to communicate with both thereof at the inner edge portion of the cavities, and said mold being provided with a gate communicating with said recess between its ends whereby the metal from the gate flows in both directions through said recess to the mold cavities at the opposite ends of the seat.

GEORGE A. AGNEW. 

